The City of Chicago was concerned about the rooftops and liability. There are several permits involved for each building and they are required to be inspected by a city building inspector three (or four?) times per year. The permits are expensive and unless they get approval they are not granted. This was the reason that the building down the left field line was empty for most of last season (failed inspections). The LLC's were started based on a suggestion from the Department of Revenue citing liability from the City's standpoint. For example, if a rooftop has a catastrophic failure and it crashed to the ground killing people, the city, by virtue of the permit and inspection process, would be liable for damages over and above what the building's insurance could cover. As a result of that exposure, the city requested that the liability insurance be set at a certain level. To limit the individual exposure to liability, LLC's were the logical arrangement. The permit/inspection process is one of the ways the city can put pressure on the rooftop owners (delaying inspections, failing inspections etc). Interesting. Thanks for clarifying.